Conventionally, there has been proposed a technology of oscillating (vibrating) a projection optical member such as an optical lens or a fluorescent body in a projection optical instrument and thereby preventing a particular region of the projection optical member from being continuously irradiated with a condensed light flux emitted from a light source unit (see Patent References 1 to 3, for example).
The Patent Reference 1 describes a technology of oscillating a lens with a vibration generator to vary the relative positions of a color wheel and an optical axis of the blue light from a blue light source and thus preventing a particular region of a fluorescent material layer applied on the color wheel from being irradiated with the blue light. The Patent Reference 1 also mentions that a linear actuator can be employed as the vibration generator.
The Patent Reference 2 describes a technology of moving a movable lens with a lens drive mechanism. The lens drive mechanism includes an X-axis drive mechanism unit and a Y-axis drive mechanism unit.
The Patent Reference 3 describes a vibration unit that vibrates at least one of a laser light source unit and a light emission member by using vibration of a vehicle. According to the description, the vibration unit includes an elastic body, which is illustrated as a coil spring in the embodiment and may also be a different type of spring member such as a torsion spring, an elastomer such as rubber, a gel body, a sponge body, or the like. According to the description, the vibration unit also includes a rod and a stopper; the light emission member is a plate-like member substantially in a fan shape; the rod is inserted into a part of the light emission member in the vicinity of the center of the fan shape; the light emission member is rotatably connected to the rod as a rotary shaft; and the light emission member is vibrated around the rod as a shaft by the vibration of the vehicle.